HP OpenVMS Systems Documentation
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DECnet-Plus for OpenVMS
Network Management
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For example: 


NCP> set x25-server destination host node mynode object 36 priority 200 -
_ subaddresses 33-34



ncl> create x25 access filter host
ncl> set x25 access filter host priority 200,subaddress range {[33..34]}
ncl> create x25 server client host
ncl> set x25 server client host filters {host} ,  -
_ncl> node LOCAL:.mynode

H.2.8 LINE Database

The LINE database contains information about all types of lines used in DECnet Phase IV. The X.25-related information is for those lines whose protocol parameter is LAPB or LAPBE.

The X.25 entries in the LINE database contain the operating characteristics of each individual connection to the PSDN at X.25 level 2 (frame level). Default values are taken mostly from the profile. Users can modify these values so that their system configurations match their PSDN subscription options. Table H-8 shows the parameter mapping rules.

Table H-8 LINE Database
Phase IV Name Phase V Entity Attribute Type
LINE modem connect line communications port Simple name
  lapb link Identifier Simple name
CONTROLLER + modem connect line N/A 1  
COUNTER TIMER + N/A    
HOLDBACK TIMER + lapb link holdback timer Unsigned
INTERFACE + lapb link interface type Enumerated {[DTE], DCE}
MAXIMUM BLOCK + lapb link maximum data size Unsigned
MAXIMUM RETRANSMITS + lapb link retry maximum Unsigned
MAXIMUM WINDOW + lapb link window size Unsigned
NETWORK lapb link profile 2,3 Simple name
PROTOCOL lapb link sequence modulus UNSIGNED 8(LAPB) or 128(LAPBE)
RECEIVE BUFFERS + lapb link receive buffers Unsigned
RETRANSMIT TIMER + lapb link acknowledge timer Unsigned
STATE + lapb link N/A 4  
+Optional parameter.
1If the CONTROLLER mode is LOOPBACK, then the startloop directive may be issued on the modem connect line using the mode attribute.
2See notes for X25-PROTOCOL NETWORK databases.
3See note on NETWORK for the X25-PROTOCOL DTE database.
4Now controlled by the enable or disable directives.

For example: 


NCP> define line dsv-0-0 network mynet protocol lapb state on



ncl> create modem connect line dsv-0 communication port DSV-0-0 -
_ncl> , profile  "NORMAL"
ncl> set modem connect line dsv-0 -
_ncl> modem control full, speed 9600 , suppress test indicator true
ncl> create lapb link dsv-0 profile  "ISO8208"
ncl> set lapb link dsv-0 physical line modem connect line dsv-0 ,  -
_ncl> acknowledge timer 2718 ,  holdback timer 1359 ,  maximum data size 1031 -
_ncl> ,  window size 7

H.2.9 X29-SERVER Database

The X29-SERVER database serves as the incoming X.29 call handler and controls the number of incoming X.29 connections on the system. In DECnet Phase V, it is merged with the X.25 call handler (X25 Access module and x25 access application entity). Table H-9 shows the parameter mapping rules.

Table H-9 X29-SERVER Database
Phase IV Name Phase V Entity
MODULE X29-SERVER N/A
COUNTER TIMER + N/A
MAXIMUM CIRCUITS + N/A
STATE + x25 access application x29_login
+Optional parameter.

H.2.10 X29-SERVER Destination Database

Each destination either points to an entry in the DECnet-VAX OBJECT database or it contains no object record. In the former case, the object identifies a command procedure to invoke. (VAX P.S.I. does not support executable images.) In the latter case, the call is considered to be for LOGINOUT.

In DECnet Phase V, objects are replaced by x25 access application entities. Each application specifies a set of filters to listen for incoming calls by using the filters attribute. The file attribute identifies a command procedure to invoke when a call is received. The type attribute for these applications should be set to X29 or X29 login if the call goes to LOGINOUT.

Table H-10 shows the parameter mapping rules.

Table H-10 X29-SERVER Destination Database
Phase IV Name Phase V Entity Attribute Type
DESTINATION x25 access filter 1 Identifier Simple name
  x25 access application 1 filters Set of simple name
  x25 access application type X29 or X29 login 2
OBJECT + x25 access application Identifier Simple name
USER x25 access application user Latin1String
PASSWORD N/A N/A N/A
ACCOUNT + x25 access application account 3 Latin1String
CALL MASK + x25 access filter call data mask Octet string
CALL VALUE + x25 access filter call data value Octet string
CALLED ADDRESS + x25 access filter originally called address DTE address
EXTENSION MASK + x25 access filter called address extension mask Octet string
EXTENSION VALUE + x25 access filter called address extension value Octet string
GROUP + x25 access filter group Simple name
INCOMING ADDRESS + x25 access filter incoming dte address DTE address
NETWORK + x25 access filter inbound dte class Simple name
PRIORITY + x25 access filter priority Unsigned
RECEIVING DTE + x25 access filter receiving dte address DTE address
REDIRECT REASON + x25 access filter redirect reason Enumerated {[Not Specified], Busy, Out of Order, Systematic}
SENDING ADDRESS + x25 access filter sending dte address DTE address
SUBADDRESSES + x25 access filter subaddress range Set of range of unsigned
+Optional parameter.
1Used for more than one attribute, due to a split of function between the x25 access filter and x25 access application entities.
2X25 Access Application type should be X29 for this type of destination unless no object is specified, in which case it is X29 login.
3Not supported in all implementations.

H.2.11 X.25 Information in the CIRCUIT Database

The CIRCUIT database contains information on several distinct types of X.25 circuits. There are two major types: those used by Routing (DLM circuits) and those used by X.25 applications ("native" PVCs).
  • Routing circuits have the OWNER qualifier set to EXECUTOR and the TYPE qualifier set to PERMANENT, OUTGOING, or INCOMING. There are three separate types of routing circuits over X.25 in DECnet Phase IV.
    • Permanent: Use an X.25 permanent virtual circuit (PVC) to provide a datalink service analogous to a leased line. Section H.2.11.3 covers this type of circuit.
    • Outgoing: Use an X.25 switched virtual circuit (SVC) to provide the datalink service. Calls are initiated to a remote system that is identified by the NETWORK and NUMBER qualifiers. Section H.2.11.1 covers this type of circuit.
    • Incoming: Use an X.25 switched virtual circuit (SVC) to provide the datalink service. Calls are received from one or more remote systems, with access controlled by the NETWORK and NUMBER qualifiers. Section H.2.11.2 covers this type of circuit.
  • X.25 application PVC circuits should have the TYPE qualifier set to PERMANENT and have no OWNER qualifier specified. Section H.2.11.4 covers this type of circuit.

Although the PVC entities in Phase IV management are contained in the CIRCUIT database, they are invalid unless they can use an X25-PROTOCOL DTE database. This fact is important in DECnet Phase V because PVCs are child entities of x25 protocol dte entities.

Phase IV DLM circuits correspond to the X.25 static incoming, static outgoing, and permanent circuits used by DECnet Phase V routing over the Connectionless-Mode Network Service (CLNS). The following sections describe how these circuit types are configured for DECnet Phase V.

Refer to Chapter 8 for a more detailed description of how DECnet Phase V routing uses X.25.

H.2.11.1 DLM Outgoing Circuit

Phase IV DLM circuits of type OUTGOING are replaced by routing circuits of type x25 static outgoing in DECnet Phase V. The circuit's data link entity characteristic is set to X25 access. There is an additional parameter, initial minimum timer, that clears the circuit if no adjacency has been established when this timer expires.

Parameters for the outgoing call are defined by an associated X25 Access template which is specified by the routing circuit template attribute.

Table H-11 shows the parameter mapping rules.

Table H-11 DLM Outgoing Circuit DLM Database
Phase IV Name Phase V Entity Attribute Type
CIRCUIT routing circuit Identifier Simple name
COST + N/A 3    
COUNTER TIMER + N/A    
DTE + N/A    
HELLO TIMER + N/A 3    
MAXIMUM DATA + x25 access template 5 packet size Unsigned
MAXIMUM RECALLS + routing circuit maximum call attempts Unsigned
MAXIMUM WINDOW + x25 access template 5 window size Unsigned
NETWORK x25 access template 5 dte class Simple name
NUMBER x25 access template 5 destination dte address DTE address
OWNER N/A    
RECALL TIMER + routing circuit recall timer Unsigned
STATE + routing circuit N/A 1  
TYPE N/A    
USAGE routing circuit type 2 x25 static outgoing
VERIFICATION + routing circuit receive verifier 4 Hex string
  routing circuit transmit verifier 4 Hex string
+Optional parameter.
1Now controlled by the enable or disable directives.
2This attribute is for the create directive.
3Not currently supported.
4Should be set if the Phase IV parameter VERIFICATION is enabled.
5Using the template identified by the routing circuit template attribute.

For example: 


NCP> set circuit x25-out usage outgoing network mynet number 12345678920 -
_ maximum data 256 maximum window 7 maximum recalls 10 recall timer 60 -
_ state on



ncl> create x25 access template rou_temp
ncl> set x25 access template rou_temp dte class mynet,destination dte -
_ncl> address 12345678920
ncl> set x25 access template rou_temp packet size 512,window size 7
ncl> create routing circuit x25-out type x25 static outgoing
ncl> set routing circuit x25-out maximum call attempts 10, recall timer 60
ncl> set routing circuit x25-out template rou_temp
ncl> enable routing circuit x25-out

H.2.11.2 DLM Incoming Circuit

Phase IV DLM circuits of type INCOMING are replaced by routing circuits of type x25 static incoming in DECnet Phase V. The circuit's data link entity characteristic is set to X25 access. There is an additional parameter, initial minimum timer, that clears the circuit if no adjacency has been established when this timer expires.

Parameters for call negotiation can be defined by an associated X25 Access template which is specified by the routing circuit template attribute.

Parameters for incoming call capture are defined by one or more X25 Access filters which are determined by the routing circuit x25 filters attribute.

When setting up an X25 Access filter for use with this type of circuit, specify the following filter characteristics for calls originating from DECnet Phase V systems:

  • call data mask %xff
  • call data value %x81

For calls originating from a Phase IV DLM system, use the subaddress range filter characteristic to select calls on the basis of the DTE subaddress or the call data value filter characteristic to select calls on the basis of the call data string DECNET_DLM.

Table H-12 shows the parameter mapping rules.

Table H-12 DLM Incoming Circuit Database
Phase IV Name Phase V Entity Attribute Type
CIRCUIT routing circuit Identifier Simple name
COST + routing circuit N/A 3  
COUNTER TIMER + N/A    
DTE + x25 access filter N/A  
HELLO TIMER + routing circuit N/A 3  
MAXIMUM DATA + x25 access template packet size Unsigned
MAXIMUM WINDOW + x25 access template window size Unsigned
NETWORK + x25 access filter inbound dte class Simple name
NUMBER + x25 access filter sending dte address DTE address
OWNER N/A    
STATE + N/A 1    
TYPE N/A    
USAGE routing circuit type x25 static incoming
VERIFICATION + routing circuit receive verifier 4 Hex string
  routing circuit transmit verifier 4 Hex string
+Optional parameter.
1Now controlled by the enable or disable directives.
3Not currently supported.
4Should be set if the Phase IV parameter VERIFICATION is enabled.

For example: 


NCP> set executor subaddresses 20-30
NCP> set circuit x25-inc usage incoming network mynet -
_ maximum data 256 maximum window 7
NCP> set circuit x25-inc sta on



ncl> create x25 access filter rou_filt
ncl> set x25 access filter rou_filt subaddress range {[20..30]}, inbound dte -
_ncl> class mynet
ncl> create routing circuit x25-inc type x25 static incoming
ncl> set routing circuit x25-inc x25 filters {rou_filt},template rou_temp
ncl> enable routing circuit x25-inc

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